<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>加法</title>
</head>
<body>
<form action="./add" method="post">
a：<input id="a" type="text" name="a">
b：<input id="b" type="text" name="b">
<input type="submit" value="=">
</form>
</body>
</html>